Document ES 1058971 U discloses an opening/closing device for a disposable flexible container for wet wipes or other products. The flexible container is made of a sheet of impermeable flexible material arranged in the form of a flat tubular bag closed at its ends by two transverse seams and has a dispensing opening on one side through which the wet wipes are dispensed. The opening/closing device comprises an adhesive base sheet placed against a portion of the flexible container covering said dispensing opening. Said base sheet incorporates two symmetrical contour cuts separating a central collapsible flap under which there is located the dispensing opening and two narrow perimetral frame portions remaining glued to the laminar surface of the packet at all times. The collapsible flap is connected to the base sheet by a fold line acting as a hinge and has a non-adhesive gripping tab on one side thereof opposite said fold line. The mentioned symmetrical contour cuts have opposing curved end terminations between which the fold line of the central flap is defined.
The cited document ES 1058971 U has several drawbacks. Firstly, the configuration of the mentioned opposing curved terminations at the ends of the symmetrical contour cuts are stress concentrators located in the flap opening limit, which involves the risk of the base sheet material tearing and the opening/closing flap separating from the rest of the base sheet and the container if the applied force is not adjusted in moderation when opening same. Secondly, the simple fold line connecting the collapsible flap to the base sheet and acting as a hinge may not be sufficient to provide the flexibility required for the collapsible flap to remain in the open position, which means that the flap tends to close spontaneously during the operation for extracting wet wipes.
Document ES 2421381 T3 discloses an opening/closing device for a disposable flexible container comprising a flexible base sheet which, when in use, is adhered to a flexible wall of the disposable flexible container covering a dispensing opening formed therein. This base sheet has one or more contour cuts defining an opening/closing flap which is connected to the rest of the base sheet by a fold line and has a lower surface covered by a re-adherable adhesive, such that said opening/closing flap is movable between a closed position, in which the opening/closing flap is adhered to an area of the flexible wall around said dispensing opening closing same, and an open position, in which the opening/closing flap is raised, providing free access to the dispensing opening. The contour cuts include curved end portions extending outwardly with respect to the opening/closing flap and towards an end of the base sheet opposite the fold line. The base sheet comprises a lower layer and an upper layer attached to one another by an adhesive, and said fold line is formed by a continuous cut completely affecting said lower layer of the base sheet but not affecting said upper layer.
One drawback of the opening/closing device of document ES 2421381 T3 is that the upper layer must have a relatively high flexibility in order to effectively perform hinge functions, given that an excessively flexible upper layer would be incapable of keeping the opening/closing flap in the open position. If the lower layer has a relatively high rigidity to confer required consistency to the opening/closing flap, this rigidity of the material is a drawback when, as often occurs, printing is to be performed on a sheet supplied from a reel from which the lower layer of the base sheet is formed.